Special Charges By Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended						12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Special Charges [Line Items]
Special charges	$ 1,628	$ 5,347	$ 9,364	$ 27,568	$ 10,419	$ 427	$ 16,339	$ 38,414	$ 29,557
Operating Segments
Special Charges [Line Items]
Special charges							426	12,478	28,425
Operating Segments | Corporate Finance / Restructuring
Special Charges [Line Items]
Special charges							84	10,274	11,332
Operating Segments | Forensic and Litigation Consulting
Special Charges [Line Items]
Special charges							308	2,111	8,276
Operating Segments | Economic Consulting
Special Charges [Line Items]
Special charges							12	11	991
Operating Segments | Technology
Special Charges [Line Items]
Special charges							19	16	3,114
Operating Segments | Strategic Communications
Special Charges [Line Items]
Special charges							3	66	4,712
Unallocated Corporate
Special Charges [Line Items]
Special charges							$ 15,913	$ 25,936	$ 1,132